Ti(IV)-based complexes have been demonstrated as candidates for preparing hybrid and functional materials, and have received considerable attention. In this paper, hierarchical hollow titania materials with different surface nanostructures were synthesized successfully using a hydrothermal process via the transformation of a Ti(IV) oxalate complex as a precursor. Different concentrations of ammonia were used to adjust the morphologies and crystalline forms of the hydrothermal products. The hierarchical hollow anatase titania materials, HHTM-1 (cal) and HHTM-2 (cal), have high surface areas of up to 132 m2 g−1 and 84 m2 g−1, respectively, and show superior performance for dye degradation in water.

This work demonstrated that a series of ultrabright fluorescent silica nanoparticles have been synthesized and designed via the reverse microemulsion method to encapsulate (2,2′-bipyridine)2-(5-aminophenanthroline) Ru bis(hexafluorophosphate) (Rubpy-phen). Transmission electron microscopy (TEM), scanning electron microscopy (SEM), dynamic light scattering (DLS), inductively coupled plasma (ICP) and fluorescence spectra were used to study the morphology and properties of the nanoparticles. By introducing ethanol into the reaction system, the obtained uniform fluorescent nanoparticles showed monodispersity and controllable size. With an increase of nanoparticle size (from 50–180 nm), the relative brightness of the nanoparticles was greatly improved from 534 to 86972 by comparison with free dye molecules. Due to the protection of the silica matrix, the fluorescence of high concentration dye-doped silica nanoparticles (Rubpy-phen NPs) is not quenched, which results in higher fluorescence intensity and relative brightness. Moreover, the silica matrix can also protect Rubpy-phen from leakage. Due to the high brightness and biocompatibility, Rubpy-phen NPs have potential applications in the biological field.

A bi-functionalized silica nanoparticle catalyst was synthesized by both generating rare earth oxide nanoparticles in the pore channels of the mesoporous silica support and grafting salicylaldimine cobalt complex on the surface of the silica. The nanocatalyst shows a strong green luminescence upon irradiation with ultraviolet light and also shows high activity for the polymerization of isoprene. The core–shell structure of this nanocomposite can protect the rare earth oxide from dissolving in hydrochloric acid. This process could produce a novel luminescent polymer/silica composite, and the polymer/silica nanocomposite formed also shows green luminescence.

Fe@C core–shell particles were successfully synthesized by coating Fe2O3 particles with resorcinol–formaldehyde resins (RFs) and then calcining to make the RFs carbonize, and at the same time to reduce the core to Fe. Furthermore, we designed and synthesized Fe@C yolk–shell particles to increase the number of active sites on the Fe surface. Compared with pure Fe material, the Fe in these particles possesses a high surface area without serious aggregation. Tests to remove 4-chlorophenol suggest that both these kinds of particles can degrade chlorophenol rapidly and thoroughly based on a Fenton-like reaction. Using Fe@C yolk–shell particles, the chlorophenol can be degraded to a concentration below the HPLC detection limit (<0.5 mg l−1) within 12 minutes. The magnetic properties and good stability of Fe@C endow it with promising potential for water treatment.

In this study, a water-soluble Fe3+ ratiometric fluorescent sensor was designed and synthesized by encapsulating a donor–acceptor (D–A) dye 4-formacyl-triphenylamine (FTA) into silica cross-linked micellar nanoparticles (SCMNPs). The quenching of FTA-encapsulated SCMNPs (FTA-SCMNPs) on Fe3+ sensing was confirmed using the fluorescence titration method. FTA-encapsulated functionalized SCMNPs (FTA-NH2-SCMNPs and FTA-SO3H-SCMNPs) were synthesized to demonstrate the surface charge effect of nanoparticles on Fe3+ fluorescence sensing. The sensing ability of Fe3+ followed in this order: FTA-SO3H-SCMNPs > FTA-SCMNPs > FTA-NH2-SCMNPs, which indicates that particles with stronger negative charge have better sensing abilities. Moreover, linear correlation between the quenching intensity and lower concentration of Fe3+ was in accordance with the Stern–Volmer equation in FTA-SCMNPs and FTA-SO3H-SCMNPs. FTA-SO3H-SCMNPs showed good selectivity for Fe3+ detection. Because of the charge effect of functionalized SCMNPs on a dye-doped Fe3+ sensing system, these kinds of nanoparticles offered possibilities to construct sensing ability-enhanced fluorescence-quenching sensors by tuning the surface charge.

Enzyme and voltage stimuli are more biologically compatible in the field of stimuli-responsive systems and release systems based on β-cyclodextrin (CD) and ferrocene (Fc) have attracted much attention. Herein, mesoporous silica nanoparticles (MSNs) have been functionalized with the ferrocenyl moiety (Fc) which interacts with β-cyclodextrin (β-CD) to form an inclusion complex on the opening of the pores. The size of the inclusion complex results in a barrier to the opening of the pores. Based on these characteristics, MSNs with nanovalves have been developed as a release system. The release system shows a clear response to heme protein (horseradish peroxidase or hemoglobin) and H2O2, glucose oxidase (GOD) with horseradish peroxidase (HRP) and glucose, or +1.5 V based on an oxidation stimulus mechanism. Modulating the amount of enzyme or the discretion of the voltage makes the release system a controlled one.

Correction for ‘Enzyme and voltage stimuli-responsive controlled release system based on β-cyclodextrin-capped mesoporous silica nanoparticles’ by Yu Xiao et al., Dalton Trans., 2015, 44, 4355–4361.

A series of mesoporous organosilicas with different phenyl group content have been synthesized for the immobilization of Heme proteins. A higher number of phenyl groups are conducive to immobilization of Heme proteins and improvement of the activity of the immobilized enzymes. The amount of immobilized horseradish peroxidase (HRP), myoglobin (Mb) and hemoglobin (Hb) is 35 mg, 51 mg and 244 mg, respectively, with 1 g of mesoporous organosilica. In particular, the immobilization efficiency of Mb can reach 100%. A sensor utilizing HRP immobilized in mesoporous organosilica is constructed on a glassy carbon electrode. In buffer solution (pH 6.0), the modified electrode shows an electrochemical response towards catechol.

•Pt is electrochemically deposited on Au/C catalyst coated on GC substrate.•The deposition of Pt improves the activity of Au/C for ethanol oxidation.•The behaviors of Pt–Au/C catalysts with different Pt loadings are investigated.The electrochemical deposition of Pt on Au nanoparticles loaded on carbon black and coated on glassy carbon (GC) electrode and the electrocatalytic oxidation of ethanol on Pt-modified Au/C catalysts are investigated. Structure analysis shows a uniform distribution of the metal nanoparticles on carbon black and a partial coverage of the Au surface by the deposited Pt. Cyclic voltammetric (CV) results display that the deposition of a small amount of Pt significantly improves the activity of the Au/C catalyst for ethanol oxidation in alkaline solution in terms of oxidation potential and current density. For example, the peak on the Pt-modified Au/C catalyst with a Pt:Au atomic ratio of 1:463 shows the onset oxidation potential close to that on Pt/C catalyst but the peak current density several times higher than that on Au/C and Pt/C catalysts. In the wide range of Pt loadings the Pt-modified Au/C catalysts exhibit considerably higher activity than Au/C and Pt/C catalysts. The modification of Au/C with Pt is found to be very effective for improving the activity of the Au/C catalyst towards ethanol oxidation.

This work demonstrates a luminescent chemosensor based on silica cross-linked micellar nanoparticles (SCMNPs) designed by encapsulating a phenothiazine-derived Schiff base, (4E)-4-((10-dodecyl-10H-phenothiazin-7-yl)methyleneamino)-1,2-dihydro-1,5-dimethyl-2-phenylpyrazol-3-one (EDDP), for the selective detection of Fe3+. The encapsulation of EDDP inside SCMNPs (EDDP–SCMNPs) can avoid the metal (Fe3+/Fe2+)-promoted hydrolysis of EDDP and, thus, exhibit highly selective determination of Fe3+. The electron transfer (ET) from EDDP in the core to Fe3+ adsorbed on the shell of EDDP–SCMNPs was verified using UV-vis absorption, fluorescent emission and 3D fluorescence spectra. Moreover, EDDP–SCMNPs showed no sensing ability of Fe2+ due to the weak electron-accepting ability of Fe2+. Significantly, because of their ultrasmall size, nontoxicity, good water solubility and biocompatibility, EDDP-SCMNPs have potential applications in biological systems.

Ordered mesoporous MnO2 nanoarrays were successfully prepared via a vacuum-assisted nanocasting route from an SBA-15 template. To achieve better purification performance for As(III), iron oxides with varied ratios were dispersed into the 2D hexagonal channels, and a series of FeMn-x adsorbents were obtained. Consisting of both iron and manganese oxides, these adsorbents could realize powerful oxidation and effective adsorption of As(III) simultaneously, revealing a synergetic arsenic removal process. The saturation adsorption capacity was 10.55 mg g−1 and >95% adsorption stability could be reached within a relatively short time. Furthermore, owing to the optimum Fe/Mn ratio, the FeMn-2 sample could easily bring the residual concentration down to below 10 ppb, when dealing with trace As(III) concentrations as low as 300 ppb, which provides a convenient method to efficiently capture trace As(III) from water for in-depth purification.

Novel hierarchical spinous hollow titania hexagonal prisms are prepared through a facile fluorine-free self-template route using Ti2O3(H2O)2(C2O4)·H2O (TC) hexagonal prisms as a precursor. The hollowing transformation can be elucidated by the template-free Kirkendall effect, and diverse nanostructures can also be synthesized during the conversion process, such as the spinous core–shell and yolk–shell nanocomposites. The hierarchical hollow microparticles are composed of ultrathin nanobelts of 50–100 nm in length and about 10 nm in thickness, and possess a higher surface area of up to 163 m2 g−1 compared with solid microparticles (49 m2 g−1). This type of morphology is of great interest for lithium-ion batteries because of its shorter length for Li+ transport and better electrode–electrolyte contact.

The design of hollow mesoporous nanostructures for cascade catalytic reactions can inject new vitality into the development of nanostructures. In this study, we report a versatile cooperative template-directed coating method for the synthesis of hollow and yolk-shell mesoporous zirconium titanium oxide nanospheres with varying compositions (ZrO2 content from 0 to 100%), high surface areas (465 m2·g−1) and uniform mesopores. In particular, the hexadecylamine (HDA) used in the coating procedure serves as a soft template for silica@mesostructured metal oxide core-shell nanosphere formation. By a facile solvothermal treatment route with an ammonia solution and calcination in air, the silica@mesostructured zirconium titanium oxide spheres can be converted into highly uniform hollow zirconium titanium oxide spheres. By simply replacing hard template silica nanospheres with core-shell silica nanocomposites, the synthesis approach can be further used to prepare yolk-shell mesoporous structures through the coating and etching process. The approach is similar to the preparation of mesoporous silica nanocomposites from the self-assembly of the core, the soft template cetyltrimethylammonium bromide (CTAB) and a silica precursor and can be extended as a general method to coat mesoporous zirconium titanium oxide on other commonly used hard templates (e.g., mesoporous silica spheres, mesoporous organosilica ellipsoids, polymer spheres, and carbon nanospheres). The presence of highly permeable mesoporous channels in the zirconium titanium oxide shells has been demonstrated by the reduction of 4-nitrophenol with yolk-shell Au@mesoporous zirconium titanium oxide as the catalyst. Moreover, a cascade catalytic reaction including an acid catalyzed step and a catalytic hydrogenation to afford benzimidazole derivatives can be carried out very effectively by using the accessible acidity of the yolk-shell structured mesoporous zirconium titanium oxide spheres containing a Pd core as a bifunctional catalyst, which makes the hollow zirconium titanium oxide spheres a practicable candidate for advanced catalytic systems.

A very simple cooperative template-directed coating method is developed for the preparation of core–shell, hollow, and yolk–shell microporous carbon nanocomposites. Particularly, the cationic surfactant C16TMA+·Br− used in the coating procedure improves the core dispersion in the reaction media and serves as the soft template for mesostructured resorcinol–formaldehyde resin formation, which results in the uniform polymer and microporous carbon shell coating on most functional cores with different surface properties. The core diameter and the shell thickness of the nanocomposites can be precisely tailored. This approach is highly reproducible and scalable. Several grams of polymer and carbon nanocomposites can be easily prepared by a facile one-pot reaction. The Au@hydrophobic microporous carbon yolk–shell catalyst favors the reduction of more hydrophobic nitrobenzene than hydrophilic 4-nitrophenol by sodium borohydride, which makes this type of catalyst@carbon yolk–shell composites promising nanomaterials as selective catalysts for hydrophobic reactants.

Ceria has been widely investigated due to its astonishing properties caused by oxygen vacancies and the facile conversion between Ce3+ and Ce4+. We synthesized luminescence tuneable ceria-based CeO2:Tb3+,Ce3+ nanoparticles, in which Ce3+ was self-doped. Excess Ce3+ ions give rise to energy transfer from Ce3+ to Tb3+ in CeO2:Tb3+,Ce3+ nanoparticles. These nanoparticles show intensity tuneable green luminescence, a long lifetime and low photobleaching in water. Reactive oxygen species (ROS) can be scavenged by these nanoparticles due to the high ratio of Ce3+/Ce4+ in ceria. The luminescence intensity of CeO2:Tb3+,Ce3+ nanoparticles is sensitive to H2O2 (a ROS) concentrations. With increased H2O2 concentration, the luminescence intensity of CeO2:Tb3+,Ce3+ nanoparticles is decreased gradually. The emission intensity can be recovered by treating with ascorbic acid, and this cycling can be repeated, which reveals good anti-fatigue properties of CeO2:Tb3+,Ce3+ nanoparticles. These attractive properties make CeO2:Tb3+,Ce3+ nanoparticles potential materials for ROS detection.

In this study, a new immobilization method was exploited to encapsulate β-galactosidase (β-gal) from Aspergillus oryzae using aggregated core–shell silica nanoparticles as a matrix. Transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy were used to characterize the material encapsulated β-gal. Compared to the free β-gal, the encapsulated β-gal shows a broader pH tolerance and thermal stability. Furthermore, the encapsulated β-gal shows better storage stability over 30 days. After nine cycles of hydrolytic reaction, the encapsulated β-gal still maintains 94.2% of its initial activity, which indicates that the β-gal exhibits excellent reusability after encapsulation.

A general synthetic procedure for highly ordered and well-dispersed periodic mesoporous organosilica (PMO) nanoparticles is reported based on a single cationic surfactant cetyltrimethylammonium bromide (CTAB) and simple silica sources with organic bridging groups via an ammonia-catalyzed sol–gel reaction. By changing the bridging group in the silica sources, the pore structures of the as-made particles with three-dimensional hexagonal (P63/mmc), cubic (Pm3n), two-dimensional hexagonal (P6mm), and wormlike structure were evidenced by powder X-ray diffraction analysis (XRD) and transmission electron microscopy (TEM). The size range of the nanoparticles can be adjusted from 30 nm to 500 nm by variation of the ammonia concentration or the co-solvent content of the reaction medium. The PMO nanoparticles with high concentration of organic groups in the framework offered good thermal stability, good dispersion in low polarity solvent and high adsorption of small hydrophobic molecules. Finally, the dye functionalized PMO nanoparticles show low cytotoxicity and excellent cell permeability, which offers great potential for biomedical applications.

This work demonstrated that water-soluble fluorescent hybrid materials can be successfully synthesized by use of silica cross-linked micellar nanoparticles (SCMNPs) as scaffolds to encapsulate fluorescent conjugated dyes for pH sensing, porphyrin sensing and tunable colour emission. Three dyes were separately encapsulated inside SCMNPs (short to dye–SCMNPs). Each of the dye–SCMNPs indicated longer lifetime in water than that of free dye dissolved in organic solvent. The 7-(hexadecyloxy) coumarin-3-ethylformate (HCE) encapsulated inside SCMNPs (HCE–SCMNPs) exhibited fluorescence quenching by pH change in aqueous media. Furthermore, it was confirmed that the radiative and nonradiative energy transfer processes both occurred between HCE–SCMNPs and tetraphenyl-porphyrin (TPP), which were used to synthesize the water-soluble TPP sensor. Significantly, HCE–SCMNPs doped with 5,12-dicotyl-quinacridone (8CQA) and TPP showed water-soluble white light emission (CIE (0.29, 0.34)) upon singlet excitation of 376 nm due to colour adjustment of 8CQA and energy transfer from HCE (donor) to TPP (acceptor).

Metal–organic polyhedra (MOP) nanocages were successfully surface functionalized via ionic self-assembly and the ordered honeycomb architecture of the encapsulated MOP nanocages was also fabricated at the air/water surface. The results provide a novel synthetic method and membrane processing technique of amphiphilic MOP nanocages for various applications.

Cooperative self-assembly of metal ions, bridging ligands and surfactants is an effective method to prepare mesostructured metal–organic frameworks (MOFs). In this study, we use quaternary ammonium surfactants with different head groups as templates to examine their effects on the structure and morphology of mesostructured MOFs formed by Cu2+ and 5-hydroxy-1,3-benzenedicarboxylic acid. In the presence of low surfactant concentrations, mesostructured MOFs with a variety of morphologies have been synthesized, having disordered, lamellar, p6mm or Pmn structure accordingly by increasing surfactant charge density. The particle size of mesostructured MOFs can be controlled from 200 to 600 nm by adjusting the molar ratio of ligand to surfactant. Comparing our experimental results with the synthesis of mesoporous silicas, we find that they follow a similar assembly process and the charge matching between surfactant and MOF framework plays a key role in the formation of mesostructures.

Cooperative adsorbents, designed on the basis of molecular structural features of targeted pollutant, were made by simultaneous grafting of two different organic functional groups on mesoporous SiO2 material SBA-15 for removal of low concentration organic pollutants in water. In this study, eosin, 4-nonylphenol (4-NP) and di-n-butyl-phthalate (DBP) were chosen as model compounds. For molecule-specific adsorption, we synthesized three corresponding cooperative adsorbents: diamine/phenyl-SBA-15, diamine/cetyl-SBA-15 and phenyl/cetyl-SBA-15, respectively. These bifunctionalized adsorbents were prepared using two appropriate organosilanes among N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-phenoxypropyldimethylchlorosilane and n-hexadecyltriethoxysilane to modify the surface of SAB-15. The XRD, TEM, IR, N2 adsorption, 29Si MAS NMR and CHN elemental analysis measurements reveal that all cooperative adsorbents not only maintain ordered mesopores of SBA-15, but also possess characteristics of the two organic functional groups. Compared with the monofunctionalized adsorbents and their physical mixtures, the cooperative adsorbents show much higher adsorption capacity and efficiency for model pollutants at low concentration. The maximal adsorption amounts of eosin, 4-NP and DBP are 0.59, 1.49 and 1.56 mmol g−1 on corresponding cooperative adsorbents, respectively. Especially, 99.95% of eosin can be removed from low concentration aqueous solution. The experimental results confirm that the cooperative effect of two functional groups on the same solid surface leads to excellent adsorption performance of bifunctionalized adsorbents.

A novel design strategy to synthesize highly ordered hexagonally mesostructured metal–organic framework materials was successfully explored, which means the realization of directly cooperative self-assembly of metal ions, bridging ligands and surfactants in an aqueous system.

We chose dipicolinic acid as a tridentate chelating unit featuring ONO donors to react with lanthanide(III) ions to yield tight and protective N3O6 environments around the lanthanide(III) ions. We immobilized the lanthanide(III)-dipicolinic acid complexes on colloidal mesoporous silica with diameter smaller than 100 nm by a covalent bond grafting technique and obtained nearly monodisperse luminescent Eu-dpa-Si and Tb-dpa-Si functionalized hybrid mesoporous silica nanomaterials. These hybrid nanomaterials were characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, nitrogen adsorption-desorption, and photoluminescence spectroscopic techniques. The hybrid mesoporous silica nanoparticles exhibit intense emission lines upon UV-light irradiation, owing to the effective intramolecular energy transfer from the chromophore to the central lanthanide Eu3+ and Tb3+ ions. Furthermore, the functionalized nanomaterials can be turned to white light materials after annealing at high temperature.

Using commercially activated carbon, we developed a simple and effective direct chemical oxidation route to prepare good biocompatible multicolor photoluminescent carbon dots.

Lanthanide(III) (Eu and Tb)-imidazoledicarboxylic acid complexes were immobilized on colloidal mesoporous silica with diameter smaller than 100 nm by covalent bond grafting technique and uniform and monodisperse luminescent Eu-idc-Si and Tb-bidc-Si functionalized mesoporous silica hybrid nanomaterials (MSNs) were obtained. The lanthanide(III) complexes-functionalized MSNs were characterized by fluorescence spectra, scanning electron microscopy, transmission electron microscopy, nitrogen adsorption−desorption, and powder X-ray diffraction. The hybrid nanomaterials Eu-idc-Si and Tb-bidc-Si functionalized MSNs show strong red and green photoluminescence upon irradiation with ultraviolet light, respectively. Both hybrid nanomaterials exhibit long lifetimes. The mesoporous silica nanoparticles are stable colloid and may have some advantages for potential applications in drug delivery or optical imaging.

Size-tunable silica cross-linked micellar core−shell nanoparticles (SCMCSNs) were successfully synthesized from a Pluronic nonionic surfactant (F127) template system with organic swelling agents such as 1,3,5-trimethylbenzene (TMB) and octanoic acid at room temperature. The size and morphology of SCMCSNs were directly evidenced by TEM imaging and DLS measurements (up to ∼90 nm). Pyrene and coumarin 153 (C153) were used as fluorescent probe molecules to investigate the effect and location of swelling agent molecules. Papaverine as a model drug was used to measure the loading capacity and release property of nanoparticles. The swelling agents can enlarge the nanoparticle size and improve the drug loading capacity of nanoparticles. Moreover, the carboxylic acid group of fatty acid can adjust the release behavior of the nanoparticles.

One advanced synthesis strategy for monodisperse silica cross-linked micellar core−shell nanoparticles (SCMCSNs) involves the use of organosilane termination agent RnSi(OR′)4 − n. In this study, we investigated the effects of the organosilane termination agent in the formation of SCMCSNs. Experimental data (synthesis results, 29Si MAS NMR, molecule probe fluorescence spectra, etc.) from a synthesis system with Pluronic F127 as the template indicate that organosilane either covers or reacts with the surface Si−OH groups of nanoparticles. The reduction of reactive surface Si−OH groups helps to stabilize nanoparticles by avoiding aggregation. The terminating behavior of organosilane is determined by its molecular structure, including (1) the value of n, (2) the length of hydrocarbon chain R, and (3) the charge of R. Effective organosilane termination agents are also applicable to other synthesis mixtures such as the systems using Si(OC2H4OH)4 as the silica source or F108 or Brij 700 as the template. Furthermore, we can obtain monodisperse nanoparticles by using the trisodium salt of triacetic acid N-(trimethoxysilylpropyl)ethylenediamine (TANED), which acts not only as a termination agent for the successful synthesis of SCMCSNs but also as a functional group to improve the performance of SCMCSNs in potential applications.

The cooperative self-assembly of silica species and cationic surfactant cetyltrimethylammonium chloride (CTA+Cl− or CTAC) and the formation of mesoporous silica nanoparticles occur following the hydrolysis and condensation of silica precursor TEOS in the solution. The particle size can be controlled from ∼25 nm to ∼200 nm by adding suitable additive agents (e.g., inorganic bases, alcohols) which affect the hydrolysis and condensation of silica species. The in situ pH measurement of synthesis system is introduced to investigate the formation process of mesoporous silica nanoparticles. Our results show that a certain acid−base buffer capacity of the reaction mixture in a range of pH 6−10 is essential for the formation of mesoporous silica nanoparticles in the TEOS−CTA+ system. The nucleation and growth process of the nanoparticles can be extended into the self-assembly system of inorganic−surfactant and the formation of mesophase in aqueous media.

A novel design strategy to synthesize highly ordered hexagonally mesostructured metal–organic framework materials was successfully explored, which means the realization of directly cooperative self-assembly of metal ions, bridging ligands and surfactants in an aqueous system.

Using commercially activated carbon, we developed a simple and effective direct chemical oxidation route to prepare good biocompatible multicolor photoluminescent carbon dots.

In this study, a water-soluble Fe3+ ratiometric fluorescent sensor was designed and synthesized by encapsulating a donor–acceptor (D–A) dye 4-formacyl-triphenylamine (FTA) into silica cross-linked micellar nanoparticles (SCMNPs). The quenching of FTA-encapsulated SCMNPs (FTA-SCMNPs) on Fe3+ sensing was confirmed using the fluorescence titration method. FTA-encapsulated functionalized SCMNPs (FTA-NH2-SCMNPs and FTA-SO3H-SCMNPs) were synthesized to demonstrate the surface charge effect of nanoparticles on Fe3+ fluorescence sensing. The sensing ability of Fe3+ followed in this order: FTA-SO3H-SCMNPs > FTA-SCMNPs > FTA-NH2-SCMNPs, which indicates that particles with stronger negative charge have better sensing abilities. Moreover, linear correlation between the quenching intensity and lower concentration of Fe3+ was in accordance with the Stern–Volmer equation in FTA-SCMNPs and FTA-SO3H-SCMNPs. FTA-SO3H-SCMNPs showed good selectivity for Fe3+ detection. Because of the charge effect of functionalized SCMNPs on a dye-doped Fe3+ sensing system, these kinds of nanoparticles offered possibilities to construct sensing ability-enhanced fluorescence-quenching sensors by tuning the surface charge.

This work demonstrates a luminescent chemosensor based on silica cross-linked micellar nanoparticles (SCMNPs) designed by encapsulating a phenothiazine-derived Schiff base, (4E)-4-((10-dodecyl-10H-phenothiazin-7-yl)methyleneamino)-1,2-dihydro-1,5-dimethyl-2-phenylpyrazol-3-one (EDDP), for the selective detection of Fe3+. The encapsulation of EDDP inside SCMNPs (EDDP–SCMNPs) can avoid the metal (Fe3+/Fe2+)-promoted hydrolysis of EDDP and, thus, exhibit highly selective determination of Fe3+. The electron transfer (ET) from EDDP in the core to Fe3+ adsorbed on the shell of EDDP–SCMNPs was verified using UV-vis absorption, fluorescent emission and 3D fluorescence spectra. Moreover, EDDP–SCMNPs showed no sensing ability of Fe2+ due to the weak electron-accepting ability of Fe2+. Significantly, because of their ultrasmall size, nontoxicity, good water solubility and biocompatibility, EDDP-SCMNPs have potential applications in biological systems.

Cooperative adsorbents, designed on the basis of molecular structural features of targeted pollutant, were made by simultaneous grafting of two different organic functional groups on mesoporous SiO2 material SBA-15 for removal of low concentration organic pollutants in water. In this study, eosin, 4-nonylphenol (4-NP) and di-n-butyl-phthalate (DBP) were chosen as model compounds. For molecule-specific adsorption, we synthesized three corresponding cooperative adsorbents: diamine/phenyl-SBA-15, diamine/cetyl-SBA-15 and phenyl/cetyl-SBA-15, respectively. These bifunctionalized adsorbents were prepared using two appropriate organosilanes among N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-phenoxypropyldimethylchlorosilane and n-hexadecyltriethoxysilane to modify the surface of SAB-15. The XRD, TEM, IR, N2 adsorption, 29Si MAS NMR and CHN elemental analysis measurements reveal that all cooperative adsorbents not only maintain ordered mesopores of SBA-15, but also possess characteristics of the two organic functional groups. Compared with the monofunctionalized adsorbents and their physical mixtures, the cooperative adsorbents show much higher adsorption capacity and efficiency for model pollutants at low concentration. The maximal adsorption amounts of eosin, 4-NP and DBP are 0.59, 1.49 and 1.56 mmol g−1 on corresponding cooperative adsorbents, respectively. Especially, 99.95% of eosin can be removed from low concentration aqueous solution. The experimental results confirm that the cooperative effect of two functional groups on the same solid surface leads to excellent adsorption performance of bifunctionalized adsorbents.

Ordered mesoporous MnO2 nanoarrays were successfully prepared via a vacuum-assisted nanocasting route from an SBA-15 template. To achieve better purification performance for As(III), iron oxides with varied ratios were dispersed into the 2D hexagonal channels, and a series of FeMn-x adsorbents were obtained. Consisting of both iron and manganese oxides, these adsorbents could realize powerful oxidation and effective adsorption of As(III) simultaneously, revealing a synergetic arsenic removal process. The saturation adsorption capacity was 10.55 mg g−1 and >95% adsorption stability could be reached within a relatively short time. Furthermore, owing to the optimum Fe/Mn ratio, the FeMn-2 sample could easily bring the residual concentration down to below 10 ppb, when dealing with trace As(III) concentrations as low as 300 ppb, which provides a convenient method to efficiently capture trace As(III) from water for in-depth purification.

Fe@C core–shell particles were successfully synthesized by coating Fe2O3 particles with resorcinol–formaldehyde resins (RFs) and then calcining to make the RFs carbonize, and at the same time to reduce the core to Fe. Furthermore, we designed and synthesized Fe@C yolk–shell particles to increase the number of active sites on the Fe surface. Compared with pure Fe material, the Fe in these particles possesses a high surface area without serious aggregation. Tests to remove 4-chlorophenol suggest that both these kinds of particles can degrade chlorophenol rapidly and thoroughly based on a Fenton-like reaction. Using Fe@C yolk–shell particles, the chlorophenol can be degraded to a concentration below the HPLC detection limit (<0.5 mg l−1) within 12 minutes. The magnetic properties and good stability of Fe@C endow it with promising potential for water treatment.

We chose dipicolinic acid as a tridentate chelating unit featuring ONO donors to react with lanthanide(III) ions to yield tight and protective N3O6 environments around the lanthanide(III) ions. We immobilized the lanthanide(III)-dipicolinic acid complexes on colloidal mesoporous silica with diameter smaller than 100 nm by a covalent bond grafting technique and obtained nearly monodisperse luminescent Eu-dpa-Si and Tb-dpa-Si functionalized hybrid mesoporous silica nanomaterials. These hybrid nanomaterials were characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, nitrogen adsorption-desorption, and photoluminescence spectroscopic techniques. The hybrid mesoporous silica nanoparticles exhibit intense emission lines upon UV-light irradiation, owing to the effective intramolecular energy transfer from the chromophore to the central lanthanide Eu3+ and Tb3+ ions. Furthermore, the functionalized nanomaterials can be turned to white light materials after annealing at high temperature.

Correction for ‘Enzyme and voltage stimuli-responsive controlled release system based on β-cyclodextrin-capped mesoporous silica nanoparticles’ by Yu Xiao et al., Dalton Trans., 2015, 44, 4355–4361.

Enzyme and voltage stimuli are more biologically compatible in the field of stimuli-responsive systems and release systems based on β-cyclodextrin (CD) and ferrocene (Fc) have attracted much attention. Herein, mesoporous silica nanoparticles (MSNs) have been functionalized with the ferrocenyl moiety (Fc) which interacts with β-cyclodextrin (β-CD) to form an inclusion complex on the opening of the pores. The size of the inclusion complex results in a barrier to the opening of the pores. Based on these characteristics, MSNs with nanovalves have been developed as a release system. The release system shows a clear response to heme protein (horseradish peroxidase or hemoglobin) and H2O2, glucose oxidase (GOD) with horseradish peroxidase (HRP) and glucose, or +1.5 V based on an oxidation stimulus mechanism. Modulating the amount of enzyme or the discretion of the voltage makes the release system a controlled one.

Ti(IV)-based complexes have been demonstrated as candidates for preparing hybrid and functional materials, and have received considerable attention. In this paper, hierarchical hollow titania materials with different surface nanostructures were synthesized successfully using a hydrothermal process via the transformation of a Ti(IV) oxalate complex as a precursor. Different concentrations of ammonia were used to adjust the morphologies and crystalline forms of the hydrothermal products. The hierarchical hollow anatase titania materials, HHTM-1 (cal) and HHTM-2 (cal), have high surface areas of up to 132 m2 g−1 and 84 m2 g−1, respectively, and show superior performance for dye degradation in water.

Metal–organic polyhedra (MOP) nanocages were successfully surface functionalized via ionic self-assembly and the ordered honeycomb architecture of the encapsulated MOP nanocages was also fabricated at the air/water surface. The results provide a novel synthetic method and membrane processing technique of amphiphilic MOP nanocages for various applications.